Carbon nanotubes, in particular, single-walled carbon nanotubes have prominent electronic characteristics, optical characteristics, mechanical characteristics, thermal characteristics and the like, and thus, those are expected to be applied in the next-generation nano-devices.
In particular, an application to a solar cell has been expected. For example, Non-Patent Document 1 discloses a solar cell comprising an n-type Si and single-walled carbon nanotubes, and it is disclosed that the cell can provide photo conversion efficiency of 2.4%.
Further, for example, Non-Patent Document 2 relates to multi-walled carbon nanotubes, wherein when a vertically aligned multi-walled carbon nanotube film was soaked in acetone and then dried, it is confirmed by the phenomenon that the film was shrunk. Non-Patent Document 3 further developed the technology of Non-Patent Document 2, and discloses that the multi-walled carbon nanotubes can provide a fine honeycomb structure.